<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>两列布局</title>
  <style>
    .main{
      float:left;
      width:200px;
      height:400px;
      background:green;
    }
    .aside{
      height:400px;
      margin-left:210px;
      background:red;
    }
  </style>
</head>
<body>
  <div class="main"></div>
  <div class="aside"></div>
</body>
</html>
